The present invention is related generally to the purification of hydrogen gas, and more specifically to hydrogen purification devices, components and fuel processing and fuel cell systems containing the same.
Purified hydrogen is used in the manufacture of many products including metals, edible fats and oils, and semiconductors and microelectronics. Purified hydrogen is also an important fuel source for many energy conversion devices. For example, fuel cells use purified hydrogen and an oxidant to produce an electrical potential. Various processes and devices may be used to produce the hydrogen gas that is consumed by the fuel cells. However, many hydrogen-production processes produce an impure hydrogen stream, which may also be referred to as a mixed gas stream that contains hydrogen gas. Prior to delivering this stream to a fuel cell or stack of fuel cells, the mixed gas stream may be purified, such as to remove undesirable impurities.
The present invention is directed to hydrogen purification devices, components of hydrogen purification devices, and fuel processing and fuel cell systems that include hydrogen purification devices. The hydrogen purification devices include an enclosure that contains a separation assembly adapted to receive a mixed gas stream containing hydrogen gas and to produce a stream that contains pure or at least substantially pure hydrogen gas therefrom. The separation assembly includes at least one hydrogen-permeable and/or hydrogen-selective membrane, and in some embodiments includes at least one membrane envelope that includes a pair of generally opposed membrane regions that define a harvesting conduit therebetween and which are separated by a support. The enclosure includes components that are formed from materials having similar or the same coefficients of thermal expansion as the membrane or membranes. In some embodiments, these components include at least a portion of the support, and in some embodiments, these components include at least a portion of the enclosure.
Many other features of the present invention will become manifest to those versed in the art upon making reference to the detailed description which follows and the accompanying sheets of drawings in which preferred embodiments incorporating the principles of this invention are disclosed as illustrative examples only.